JP2001090597A - Control device for internal combustion engine - Google Patents

Abstract

PROBLEM TO BE SOLVED: To reduce the exhaust amount of NOx while reducing the exhaust amount of hydrocarbon. SOLUTION: In a control device for an internal combustion engine which has an exhaust gas cleaning catalyser 19 in an exhaust passage, a supercharger 9 for supercharging inlet air and an exhaust gas circulation means 15 for circulating part of exhaust gas into an inlet passage, a control means 50 reduces supercharging pressure supplied by the supercharger 9 and increases the circulation amount of exhaust gas supplied by the exhaust gas circulation means 15, when the internal combustion engine is judged to be in a cooled condition by a cooled condition judging means 51.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a control device for an internal combustion engine having an exhaust gas purifying catalyst, a supercharger (turbocharger), and an exhaust gas recirculation device (exhaust gas recirculation means).

[0002]

In recent years, HC, there is a need to reduce the emission of harmful substances such as NO _X to develop friendly environment engine environment. Therefore, conventionally, although in an exhaust passage of an internal combustion engine (e.g., diesel engines) and exhaust gas purifying catalyst (e.g. oxidation catalyst) is provided in order to purify the harmful components in the exhaust gas (HC, NO _X, etc.) When the engine is cold, the amount of HC generated is large because the engine is not sufficiently warmed and combustion is unstable, and when the exhaust gas temperature is low, the HC purification efficiency of the exhaust gas purifying catalyst is low. Is difficult to purify enough,
It is difficult to reduce HC emissions.

[0003] Further, a supercharging pressure variable intake system such as a turbocharger capable of adjusting the supercharging by narrowing the diameter of an exhaust gas introduction passage is provided in the intake system. ), The diameter of the exhaust gas introduction passage to the turbocharger is generally narrowed when the engine is cold, and the temperature of the exhaust gas is reduced. As a result, the HC purification rate of the exhaust gas purifying catalyst is further increased. Therefore, it is difficult to sufficiently purify the generated HC, and it is more difficult to reduce the amount of discharged HC.

As a technique for suppressing a decrease in exhaust gas temperature in a system provided with such a variable supercharging pressure intake system, for example, there is a technique disclosed in Japanese Patent Publication No. 3-24571 (publication 1). In this technique, the supercharging pressure is controlled so that the supercharging pressure is reduced during a cold state, thereby suppressing a decrease in the exhaust gas temperature and quickly warming up the exhaust gas purifying device.

[0005]

[SUMMARY OF THE INVENTION Incidentally, only perform supercharging pressure control, such as publications described above, although capable of improving the purification efficiency of the exhaust gas purifying apparatus, the emission of a harmful substance NO _X in the exhaust gas It cannot be reduced sufficiently.
Therefore, conventionally, in order to reduce the emissions of NO _X, for example, it is provided an exhaust gas recirculation device for recirculating exhaust gases (EGR device) are carried out into the intake passage.

[0006] However, when a large amount of exhaust gas is recirculated by the EGR device, the amount of HC emission increases. Therefore, even when subjected to the supercharging pressure control by the turbocharger in order to reduce the HC emission amount as described above, EGR to reduce NO _X emissions
When a large amount of exhaust gas is recirculated by the device, HC
Emissions cannot be reduced sufficiently.

[0007] The present invention has been in view conceived of the above problems, and at the same time reducing the HC emissions were as NO _X emissions can be reduced, to provide a control apparatus for an internal combustion engine The purpose is to:

[0008]

According to a first aspect of the present invention, there is provided a control apparatus for an internal combustion engine according to the present invention, wherein an exhaust gas purifying catalyst, a supercharger for supercharging intake air, And an exhaust gas recirculation unit that recirculates the part into the intake passage. In the internal combustion engine, when the cold state determination unit determines that the internal combustion engine is in a cold state, the control unit supercharges intake air. And the amount of exhaust gas recirculation by the exhaust gas recirculation means for recirculating a part of the exhaust gas into the intake passage is increased.

[0009]

Embodiments of the present invention will be described below with reference to the drawings. A control device for an internal combustion engine according to an embodiment of the present invention will be described with reference to FIGS. The internal combustion engine according to the present embodiment is configured as a direct injection type diesel engine (in-cylinder injection type internal combustion engine) 1, as shown in FIG.

In the diesel engine 1, an intake passage 3 and an exhaust passage 4 are connected to a combustion chamber 2. The intake passage 3 and the combustion chamber 2 are controlled to communicate with each other by an intake valve 5.
The communication between the exhaust passage 4 and the combustion chamber 2 is controlled by an exhaust valve 6. Further, a fuel injection nozzle 7 is also provided so as to face the combustion chamber 2, and fuel is supplied to the fuel injection nozzle 7 from a fuel injection pump in accordance with an operating position of a rack controlled by a rack actuator (not shown). It has become so. The fuel injection device is
The present invention is not limited to the above-described one, but is a pressure-accumulation chamber fuel injection device (common rail type fuel injection device) configured to store high-pressure fuel in a pressure-accumulation chamber and inject the high-pressure fuel from a nozzle by switching control of an electromagnetic valve. There may be.

An intake throttle valve 8 is provided in the intake passage 3. Then, by reducing the opening degree of the intake throttle valve 8, an EGR amount described later can be increased. Further, an exhaust gas purifying catalyst 19 is provided in the exhaust passage 4. The exhaust gas purifying catalyst 19 is constituted by, for example, an oxidation catalyst that purifies by oxidizing CO and HC in the exhaust gas. As shown in FIG. 4, the HC purification rate characteristics of the exhaust gas purifying catalyst 19 show the highest HC purification rate when the exhaust gas temperature (here, the exhaust gas temperature at the catalyst inlet) is about 300 ° C. The lower the exhaust gas temperature, the lower the HC purification rate by the exhaust gas purifying catalyst 19.

The diesel engine 1 is provided with a turbocharger (turbocharger) 9. In the turbocharger 9, the exhaust turbine is interposed in the exhaust passage 4, and a compressor connected to and driven by the exhaust turbine is interposed in the intake passage 3, and transmits the driving force of the exhaust turbine to the compressor. The intake air is pressurized. An intercooler 10 is provided downstream of the compressor in the intake passage 3 in order to reduce the temperature of the air pressurized by the compressor.

Here, the turbocharger 9 is shown in FIG.
As shown in (A) and (B), a turbocharger with a variable nozzle vane (also referred to as a variable capacity turbocharger or VG turbo)
The nozzle vanes 9c are arranged at equal intervals around a turbine blade 9b of the exhaust turbine 9a. Each nozzle vane 9c is connected to an annular ring 9d, and when the annular ring 9d rotates in the direction of the arrow in the drawing, the angle of the nozzle vanes 9c, that is, the opening degree is changed. That is, the nozzle vane 9c
The supercharging pressure (in-manifold pressure) decreases as the opening of the nozzle vane 9 becomes open, and the opening of the nozzle vane 9c becomes closed (throttle side).
, The supercharging pressure (in-mani pressure) rises.

FIG. 3A shows a case where the opening of the nozzle vane 9c is fully opened. When the opening of the nozzle vane 9c is fully opened, the supercharging pressure (in-manifold pressure) becomes minimum. . On the other hand, FIG. 3B shows a case where the opening degree of the nozzle vane 9c is fully closed.
When the opening of c is fully closed, the supercharging pressure (in-manifold pressure) becomes maximum.

Here, as shown in FIGS. 2, 3A and 3B, a VG turbo actuator 11 is connected to the annular ring 9d. Here, the VG turbo actuator 11 is an actuator whose operating position can be variably controlled by, for example, a built-in spring 11b and vacuum (negative pressure), and is moved from the tank 12 to the control room 11a of the VG turbo actuator 11. The operation position is controlled by switching the supply state of the vacuum by the electromagnetic valves 13 and 14, whereby the opening degree of the nozzle vane 9c is controlled to open and close so that a required supercharging pressure is obtained. The tank 12 is supplied with vacuum by a vacuum pump.

The VG turbo actuator 11
Is not limited to such a configuration,
A device that can adjust the operating position stepwise may be used. Further, the VG turbo actuator 11 is not limited to the one that operates according to the supply state of the vacuum, but may be another configuration as long as it is connected to the annular ring 9d to adjust the opening of the nozzle vane 9c. May be used.

This VG turbo actuator 11 is
It is connected to a controller (ECU) 50 to be described later, and its operation is controlled based on a control signal from the controller 50. That is, the operation of the solenoid valves 13 and 14 of the VG turbo actuator 11 is controlled based on a control signal from the controller 50 according to the operation state of the diesel engine 1.

The diesel engine 1 is also provided with an exhaust gas recirculation device (exhaust gas recirculation means, EGR device) 15 for recirculating a part of the exhaust gas discharged to the exhaust passage 4 to the intake passage. . The EGR device 15 includes an exhaust gas recirculation passage (EGR passage) 1 provided to connect the intake passage 3 and the upstream side of the exhaust passage 4.
5a and an EGR attached to the EGR passage 15a.
It comprises a valve 15b and an EGR cooler 15c provided to lower the temperature of the recirculated exhaust gas. In the present embodiment, the EGR valve 15b is
It is not a mere on-off valve, but a valve whose opening itself can be changed.

The EGR valve 15b is connected to the EGR actuator 16, and the operation of the EGR actuator 16 is controlled by a controller 50 described later, whereby the opening of the EGR valve 15b is adjusted and the EGR valve 15b is connected to the intake passage 3. The flow rate of the recirculated exhaust gas (hereinafter, referred to as EGR gas or recirculated gas) is adjusted.

Here, the EGR actuator 16 is
From the vacuum pump 17 to the control chamber 15b of the EGR valve 15b
The operation position is controlled by switching the supply state of the vacuum (negative pressure) into the solenoid valve a by solenoid valves (solenoid valves) 18a and 18b.
The EGR actuator 16 is not limited to the one having such a configuration, and may be one that can adjust the operating position stepwise (for example, a stepper motor type). Also, the EGR actuator 1
6 is not limited to the one that operates according to the supply state of the vacuum, but may have another configuration as long as the opening of the EGR valve 15b can be adjusted.

The EGR actuator 16 is connected to a controller (ECU) 50 described later, and its operation is controlled based on a control signal from the controller 50. That is, based on the control signal from the controller 50 according to the operating state of the engine 1, the electromagnetic valves 18a,
The operation of 18b is controlled.

By the way, in the present embodiment, the reducing HC emissions, in order to significantly reduce the NO _X emissions by mass introduction of EGR while suppressing the increase of HC emissions, the controller (ECU, As shown in FIG. 1, the electronic control unit 50 includes a cold state determination unit 51, a supercharging pressure control unit 52, an exhaust gas recirculation amount control unit (EGR amount control unit) 53, and a target excess air ratio setting unit. 54 and an actual excess air ratio estimating means 55.

Here, the cold state determination means 51 determines whether the engine is in a cold state based on the engine cooling water temperature Tw.
This is to determine whether the engine is in a hot state. For this reason, the engine 1 is provided with an engine cooling water temperature sensor 36 at a predetermined location. The engine cooling water temperature sensor 36 is connected to the controller 50, and a detection signal from the engine cooling water temperature sensor 36 is sent to the cold state determination means 51 of the controller 50.

More specifically, the cold state determination means 51 determines whether or not the engine cooling water temperature Tw detected by the engine cooling water temperature sensor 36 is lower than a predetermined temperature Tw0. I have. If the engine coolant temperature Tw detected by the engine coolant temperature sensor 36 is lower than a predetermined temperature Tw0, it is determined that the engine is in a cold state, and the engine coolant temperature sensor 3
When the engine cooling water temperature Tw detected by step 6 is equal to or higher than a predetermined temperature Tw0 set in advance, it is determined that the engine is in a hot state.

The supercharging pressure control means 52 performs a full opening control to fully open the opening of the nozzle vane 9c of the turbocharger 9 in a low load operation region when the engine is cold, thereby reducing the supercharging pressure (in manifold pressure). The supercharging pressure control is performed as described above. That is, the supercharging pressure control means 52 is a case in which the cold-time determination means 51 determines that the engine is in the cold state, and also determines the engine speed Ne and the engine load (for example, the engine speed and the accelerator opening degree). When the average effective pressure Pme calculated on the basis of the above belongs to a low-load operation region (particularly, an operation region in which a large amount of HC is generated), a full-open control for fully opening the nozzle vane 9c of the turbocharger 9 is performed. The supercharging pressure is controlled so as to decrease.

Here, whether the engine speed Ne and the engine load (average effective pressure Pme) are in a low load operation region (particularly, an operation region in which a large amount of HC is generated) is determined as shown in FIG. The determination is made based on whether or not it belongs to the A zone in the time supercharging pressure map. In the operation region (A zone) where the amount of generated HC is large, the opening of the nozzle vane 9c of the turbocharger 9 is fully opened, and this region is also referred to as a fully opened vane opening region.

For this purpose, the engine 1 is provided with a crank angle sensor 34 and a load sensor 35 for detecting the load on the engine 1 at predetermined locations. These sensors are connected to the controller 50, and detection signals from the sensors are transmitted to the supercharging pressure control means 52 of the controller 50.
To be sent to The detection signals from these sensors are also sent to the EGR amount control means 53.

Since the engine speed Ne can be calculated based on the crank angle sensor 34, the crank angle sensor 34 is referred to as an engine speed sensor (engine speed detecting means, engine speed sensor) for convenience. Also,
As the load sensor 35, an accelerator opening sensor (APS) that detects the opening of an accelerator pedal (or the amount of depression of the accelerator) (not shown) is used. The load sensor 35
May use a rack position sensor that detects a rack position of a fuel injection pump (not shown).

The reason why the nozzle vanes 9c of the turbocharger 9 are fully opened in the low load operation range when the engine is cold as described above is as follows. That is, when the engine is cold, the engine 1 is not sufficiently warmed up, the combustion temperature in the cylinder is lower, and the generation level of HC is higher than in the case of the same load condition (low load operation range) at the time of engine temperature. Furthermore, since the combustion temperature is low, the exhaust gas temperature is also low,
When the exhaust gas temperature is low, the HC purification rate by the exhaust gas purifying catalyst 19 is at a low level as shown in FIG. Therefore, it is difficult to efficiently purify the HC generated by the exhaust gas purifying catalyst 19 provided in the exhaust passage 4.

On the other hand, in the low load operation region, a sufficient amount of intake air is supplied, so that the opening degree of the nozzle vanes 9c of the turbocharger 9 is fully opened to reduce the supercharging pressure, thereby reducing the intake pressure. There is no problem with reducing the amount of air. Here, as shown in FIG. 6 (A), as the opening degree of the nozzle vane 9c of the turbocharger 9 is increased, the supercharging pressure is reduced and the amount of fresh air is reduced, thereby reducing the in-cylinder intake air temperature. Since the temperature rises, the combustion temperature in the cylinder increases, and the exhaust gas temperature (turbine outlet temperature) at the turbine outlet of the turbocharger 9 also increases. If the EGR amount is excessively increased, the nozzle vanes 9 of the turbocharger 9
Opening the opening of c reduces the heat energy generated by the combustion, so that the turbine outlet temperature may decrease. As described above, when the turbine outlet temperature of the turbocharger 9 increases, the HC purification rate by the exhaust gas purification catalyst 19 becomes a high level. Therefore, as shown in FIG. 6B, the opening degree of the nozzle vanes 9c of the turbocharger 9 is increased. , The supercharging pressure decreases and the intake air volume decreases,
HC emission decreases.

For this reason, the HC discharge amount is reduced by performing the full-open control of the nozzle vanes 9c of the turbocharger 9 in the low load operation region in the cold state to lower the supercharging pressure and reduce the intake air amount. It is being reduced. on the other hand,
If it is determined that the engine is in the warm state (normal state) by the cold state determination means 51 or if it is determined that the engine does not belong to the operating region (A zone) where the amount of generated HC is large, the engine rotation speed sensor 34 Controller 50 based on the average effective pressure Pme calculated based on the engine rotation speed Ne detected by the engine and the load detected by the load sensor 35.
The target supercharging pressure is set using the supercharging pressure map at normal temperature (normal supercharging pressure map) as shown in FIG.
The opening degree of the nozzle vanes 9c of the turbocharger 9 is controlled so that the actual supercharging pressure (actual supercharging pressure) at the present time matches the target supercharging pressure.

Here, if the pressure difference between the target boost pressure set by the hot boost pressure map and the current actual boost pressure is equal to or greater than a predetermined value, the VG vane actuator 11
Rapidly pumping the vacuum to (i.e., raising or lowering the vacuum rapidly)
The nozzle vanes 9c are controlled with good responsiveness.

Here, as shown in FIG. 7, the supercharging pressure map at the hot state is a supercharging pressure map set in consideration of fuel efficiency in order to suppress the production of sulfate (sulfate such as SO ₂ ). The map value is set such that the supercharging pressure is higher in the medium-speed / high-load operation region (normal operation region) than the map value in. Further, in order to maintain the turbine speed of the turbocharger 9 at a high speed in order to improve the starting acceleration,
The map value is set so that the supercharging pressure becomes higher in the idling operation region.

By controlling the supercharging pressure by controlling the opening of the nozzle vanes 9c of the turbocharger 9 as described above, the amount of HC emission is reduced. As described above, if the EGR amount is increased (high EGR), the NO _X generation amount can be significantly reduced. For this reason, in the present embodiment, the EGR control means 53 is further provided.

The EGR control means 53 controls the EGR valve 15b so as to adjust the amount of exhaust gas recirculated into the intake passage 3. The EGR control unit 53 controls the EGR valve 15b to increase the opening when the cold state determination unit 51 determines that the engine is in the cold state. This makes it possible to significantly reduce the amount of generated NO _X by performing a large amount of EGR in a cold state.

Here, if the EGR amount is excessively increased, HC
Since the amount of generation increases rapidly (see FIG. 6B), EG
The EGR control means 53 does not increase the R amount excessively.
The opening degree control of the EGR valve 15b is performed by controlling the in-cylinder excess air ratio λ.
Is performed as a control parameter.
Specifically, the EGR control means 53 is provided with the cold state determination means 5.
If it is determined that the vehicle is in a cold state by the method 1, the target air
Limit target air excess set by excess ratio setting means 54
Rate λ_TwoIs estimated by the actual excess air ratio estimating means 55.
Actual air excess ratio λ ₁Deviation from Δλ₁₂(= Λ₁−λ_Two)
And this deviation Δλ₁₂Is a small amount ε₁Will be smaller than
Based on the excess air ratio λ of the opening of the EGR valve 15b
Feedback control is performed.

Note that the minute amount ε₁Means that there is no difference in HC generation
As a visible excess air ratio difference,
I will ask for it. Here, the actual excess air ratio estimating means 55
Is the inhaled volume G_cyl, EGR amount G_egr, Based on fuel injection amount, etc.
The actual excess air ratio (actual excess air ratio) λ₁Estimate
Things.

That is, the actual excess air ratio estimating means 55 calculates the intake manifold temperature [the temperature of the intake air in the intake manifold (also called the intake manifold), the intake air temperature] T _mani , the intake manifold pressure (the pressure of the intake air in the intake manifold, the intake pressure). ) P _mani ,
Atmospheric pressure P _a, based on the volumetric efficiency ηv to the engine rotational speed Ne and the engine rotational speed Ne, calculating the intake amount (intake weight flow rate) G _cyl and the EGR amount G _egr sucked into the combustion chamber 2 (in-cylinder) Then, the actual excess air ratio λ ₁ is calculated from the suction amount G _cyl and the EGR amount G _egr .

In order to calculate the suction amount G _cyl as described above,
The intake manifold temperature _Tmani , the intake manifold pressure (gauge pressure) _Pmani ,
Atmospheric pressure P _a, by taking into account the volumetric efficiency .eta.v, are to be calculated more accurately the intake quantity G _cyl. Incidentally, the intake manifold temperature T _mani, intake manifold pressure (gauge pressure) P _mani, the atmospheric pressure P _a, the volumetric efficiency ηv are the data necessary for calculating the intake amount G _cyl, that the intake amount data.

For this reason, the engine 1 includes an intake air temperature sensor (intake air temperature detecting means) 31, an intake pressure sensor (intake air pressure detecting means) 32, an atmospheric pressure sensor (atmospheric pressure detecting means) 33, a crank angle sensor 34, and the like. It is provided at a predetermined location. Then, these sensors are connected to the controller 50,
The detection signal from each sensor is sent to the actual excess air ratio estimating means 54 of the controller 50.

The intake pressure sensor 32 is also called a boost pressure sensor (boost pressure detecting means). The intake pressure sensor 32 is attached to, for example, an intake manifold of the engine 1 and detects a pressure (boost pressure) of intake air pressurized by the turbocharger 9. Moreover, volumetric efficiency ηv is to vary by the intake manifold temperature T _mani, volumetric efficiency regardless of the temperature change η
v is treated as a constant and simply the engine speed Ne,
Instead of obtaining the volumetric efficiency ηv with respect to the engine load, the actual excess air
The effect of _mani is also taken into account, and temperature correction is performed when obtaining the volume efficiency ηv. As a result, the suction amount G _cyl can be accurately calculated using the volume efficiency ηv that is accurately obtained.

The actual excess air ratio estimating means 55 sets the reference intake manifold temperature to T0, sets the reference volumetric efficiency to the reference intake manifold temperature T0 to ηv0, and sets the volumetric efficiency index to m,
The volume efficiency ηv for an arbitrary intake manifold temperature T _mani is obtained by the following equation (1) for each engine speed Ne and engine load. ηv / ηv0 = (T _mani / T0) ^m (1) Specifically, first, for the target engine 1, the engine rotational speed Ne and the intake manifold temperature T for each engine load are set.
A characteristic between the _mani and the volumetric efficiency ηv is obtained by a bench test, and a map for calculating the volumetric efficiency ηv is created based on such a characteristic between the intake manifold temperature _Tmani and the volumetric efficiency ηv.

That is, the reference intake manifold temperature T0 (for example, about 25 ° C.) for each engine speed Ne and engine load.
The reference volume efficiency ηv0 for was measured by a bench test,
Based on this, a reference volumetric efficiency map is created in which the engine rotational speed Ne and the engine load at the reference intake manifold temperature T0 (for example, about 25 ° C.) are associated with the reference volumetric efficiency ηv0.

A characteristic indicating the relationship between the intake manifold temperature T _mani and the volumetric efficiency ηv is measured by a bench test for each engine rotation speed Ne and engine load, and based on this, each engine rotation speed Ne and engine load is measured. The volumetric efficiency index m is also determined for each of them, and is used as the reference intake manifold temperature T0 (for example, about
C), a volume efficiency index map is created in which the engine speed Ne, the engine load, and the volume efficiency index m are associated with each other.

Then, a volume efficiency ηv with respect to an arbitrary intake manifold temperature T _mani , an engine rotation speed Ne, and an engine load.
Is calculated based on the reference intake manifold temperature T0 (for example, about 25 ° C.), the reference volumetric efficiency ηv0 obtained from the reference volumetric efficiency map, and the volumetric efficiency index m obtained from the volumetric efficiency index map. Next, a method of calculating the intake amount G _cyl by the actual excess air ratio estimating means 55 will be described.

The actual excess air ratio estimating means 55 calculates the following equation (2).
Temperature T represented by_mani, Intake manifold pressure P_mani
Using the calculation formula of the volumetric efficiency ηv defined by
_cyl(Kg / s). ηv = 120G_cyl/ [Ne × Vh × γ_mani(P_mani, P_a, T_mani)] (2) where Ne is the engine speed and Vh is the engine speed.
Stroke volume, γ _mani(P_mani, P_a, T_mani) Is
Specific weight of air-fuel mixture (intake air and EGR) (k
g / m^Three).

When the above equation (2) is modified, it is expressed as the following equation (3). Therefore, the actual excess air ratio estimating means 55 calculates the intake amount G _cyl using this equation (3). It is to be calculated. G _cyl = _{[Ne × Vh × ηv × γ mani} (P mani, P a, T mani) ] / 120 (3) where specific weight _{γ mani (P mani, P a} , T mani) is intake manifold pressure (gauge pressure) to (kg / m ²⁾ and P _mani, atmospheric pressure (kg / m ²⁾ and P _a, the intake manifold temperature (K) as T _mani, represented by the formula (4). In addition, let the gas constant be R [kg · m / (kg · K)].

Γ _mani = (P _mani + P _a ) / (R × T _mani ) (4) Here, the engine stroke volume Vh and the gas constant R are constants, and the engine rotation speed Ne and the intake manifold pressure P _mani , Atmospheric pressure P _a , and intake manifold temperature T _mani use the values detected by the sensors, and the volumetric efficiency ηv uses the values determined in advance by the bench test as described above using the suction amount G _cyl.
Is calculated.

Here, since the intake manifold pressure P _mani detected by the intake pressure sensor 32 is detected as a pressure difference from the atmospheric pressure, the intake pressure G _man is calculated by the atmospheric pressure sensor 33 to calculate the intake amount G _cyl. are also taken into consideration the atmospheric pressure P _a was.
However, if configured by the absolute pressure sensor so as to detect the intake manifold pressure P _mani, there is no need to consider the atmospheric pressure P _a.

[0050] Then, the real excess air rate estimating means 55 is adapted to calculate the actual excess air ratio lambda ₁ from this way inhalation volume G _{cy l} which is calculated. That is, the actual excess air ratio estimating means 55 sets the fuel injection amount (kg / s) for obtaining the desired output characteristic to Gf, and theoretically calculates the theoretical air amount (kg) necessary for completely burning 1 kg of fuel. / Kg) to L
The actual excess air ratio λ ₁ is calculated by the following equation (5), with 0 as the remaining air amount in the EGR as Ga _{, e} .

The _{λ 1 = (G a + G} a, e) / (L0 × Gf) ··· (5) where the intake amount G _cyl is the intake air amount G _a, EGR amount passing through the EGR valve 15b (Weight flow rate of EGR gas) G _egr is expressed by the following equation (6). G _cyl = G _a + G _egr (6) Therefore, the intake air amount G _a is represented by the following equation (7).

G _a = G _cyl −G _egr (7) In consideration of such a relationship, the above equation (5) is expressed as the following equation (8). λ ₁ = (G _a + G _{a, e} ) / (L 0 × G f) = (G _a + G _egr ) / (L 0 × G _f ) −G _egr / G _a = G _cyl / (L 0 × Gf) −G _egr / ( G _cyl -G _egr ) (8) The fuel injection amount Gf is the engine speed detected by the engine speed sensor 34 and the accelerator depression amount (accelerator opening) detected as the engine load by the load sensor 35. ) Based on the engine rotation speed and the fuel injection amount map in the engine load region.

The EGR amount G _egr is calculated based on signals from the EGR gas pressure sensors 41 and 42, the EGR valve temperature sensor 43, and the EGR valve lift sensor 44, as shown in FIG. That is, the EGR amount G _egr is
The specific weight of the EGR gas upstream of the EGR valve 15b is represented by γ
_Egr , the volume flow rate of the EGR gas is Q _egr, and EGR
EGR provided respectively on the upstream and downstream sides of the valve
The differential pressure calculated based on the signals from the gas pressure sensors 41 and 42 is ΔP, the temperature detected by the temperature sensor 43 disposed on the upstream side of the EGR valve is T _egr ,
EGR detected by EGR valve lift sensor 44
The effective opening area (including the flow coefficient) corresponding to the valve lift amount is defined as A _egr , and the gravitational acceleration is defined as g.
Is calculated by

G _egr = γ _egr × Q _egr = γ _egr × A _egr × [(2g × ΔP) / γ _egr ] ^1/2 = A _egr × (2g × γ _egr × ΔP) ^1/2 ··· 9) The target excess air ratio setting means 54 sets the limit target excess air ratio λ ₂ based on the operating state of the engine 1 (engine speed Ne, engine load). That is,
The target excess air ratio setting means 54 determines the limit target excess air ratio λ based on the engine rotation speed Ne detected by the engine rotation speed sensor 34 and the average effective pressure Pme calculated based on the load detected by the load sensor 35. ₂ is set.

Here, the limit target excess air ratio λ ₂ is represented by HC
Is the limit excess air ratio (minimum excess air ratio) when the EGR amount is increased to the maximum without increasing rapidly. For this reason, the target excess air ratio setting means 54 previously calculates the limit target excess air ratio λ ₂ by a bench test for each engine speed and each engine load region, and stores this as a limit target excess air ratio map. The limit target excess air ratio λ ₂ is set using this limit target excess air ratio map. By performing this way the control of the opening degree of the EGR valve 15b so as to approach the limit target excess air ratio lambda ₂ is set, while suppressing the generation amount of HC as the amount of HC is not increased rapidly within a predetermined range , NO _X generation amount can be greatly reduced.

Specifically, the EGR control means 56
The opening control of the R valve 15b is performed as follows. That is, the deviation Δλ ₁₂ (= λ ₁ −λ ₂ )
If is negative, i.e. if the actual excess air ratio lambda ₁ is smaller than the limit target excess air ratio lambda ₂ is the because it less to meet the intake air amount G _a is the limit target excess air ratio lambda _2,
In order to increase the supercharging pressure (in-manifold pressure) and increase the excess air ratio, control is performed to decrease the opening of the EGR valve 15b (to narrow the opening).

On the other hand, when the deviation Δλ ₁₂ (= λ ₁ −λ ₂ ) is positive, that is, when the actual excess air ratio λ ₁ is equal to the limit target excess air ratio λ ₂
If more greater, since it is of too high to meet the intake air amount G _a is a limit target excess air ratio lambda ₂ Conversely,
In order to reduce the supercharging pressure (in-manifold pressure) and reduce the excess air ratio, control is performed to increase the opening degree of the nozzle vane 9c of the turbocharger 9 (enlarge the opening degree).

When it is determined by the cold state determining means 51 that the engine is in the warm state (normal state), the EGR control means 56 sets the target excess air rate λ set by the target excess air rate setting means 54. The deviation Δλ ₁₀ (= λ) between ₀ and the actual excess air ratio λ ₁ estimated by the actual excess air
₁₋ λ ₀ ), and feedback control based on the excess air ratio λ of the opening degree of the EGR valve 15b is performed so that the deviation Δλ ₁₀ becomes smaller than the minute amount ε ₂ .

The minute amount ε ₂ is determined in advance by a bench test as a difference in excess air ratio such that a change in exhaust gas temperature does not affect sulfate formation. Here, the target excess air ratio setting means 54 sets the target excess air ratio λ ₀ based on the operating state of the engine 1 (engine speed Ne, engine load). That is, the target excess air ratio setting means 54 includes the engine speed sensor 34,
And a load sensor 35 for detecting the load of the engine 1
The target excess air ratio λ ₀ is set on the basis of the detection information from.

A target excess air ratio map in which the engine rotation speed, the engine load, and the target excess air ratio λ ₀ are associated is prepared in advance, and the engine rotation speed sensor 34
And a load sensor 35 for detecting the load of the engine 1
The target excess air ratio λ ₀ according to the engine rotation speed and the engine load region set based on the detection information from the target air excess ratio may be obtained from the target excess air ratio map.

More specifically, the EGR control means 53 controls the EG
The opening control of the R valve 15b is performed as follows. That is, the deviation Δλ ₁₀ (= λ ₁ −λ ₀ )
Is negative, that is, the actual excess air ratio λ ₁ is
If ₀ is smaller than, since intake air amount G _a is the smaller to meet the target excess air ratio lambda _0, the boost pressure E in order to increase the (intake manifold pressure) the actual excess air ratio by increasing
Control for reducing the opening of the GR valve 15b (decreasing the opening) is performed.

[0062] On the other hand, when the deviation _{Δλ 10 (= λ 1 -λ 0} ) is positive, i.e. if the actual excess air ratio lambda ₁ is larger than the target excess air ratio lambda ₀ is inverse to the intake air amount G _a is the target Since it is too large to satisfy the excess air ratio λ ₀ , the opening degree of the nozzle vane 9c of the turbocharger 9 is increased to reduce the supercharging pressure (in-manifold pressure) and reduce the actual excess air ratio (opening degree (Extend) control is performed.

When the deviation Δλ ₁₂ (or Δλ ₁₀ ) between the actual excess air ratio λ ₁ and the limit target excess air ratio λ ₂ (or the target excess air ratio λ ₀ ) is large, the EGR amount control means 53 enhance the responsiveness of the control, in order to be able to sufficiently suppress the generation amount of HC and NO _X during the transient may be performed a control of the opening degree of the nozzle vane 9c of the turbocharger 9 as follows.

That is, the deviation Δλ₁₂(Or Δλ_Ten) Size
Is a predetermined value E (E> ε₁, E> ε_Two)
Is the deviation Δλ₁₂(Or Δλ_Ten) According to the size of
-First control of opening of nozzle vane 9c
The amount may be changed. For example, the deviation Δλ
₁₂(Or Δλ_Ten) Is greater than or equal to the predetermined value E
[Deviation Δλ₁₂(Or Δλ_TenIf the size of) is large)
Is the deviation Δλ₁₂(Or Δλ_Ten) According to turbo charge
The initial control amount of the opening degree of the nozzle vane 9c of the locker 9 is increased.
Then, the opening degree of the nozzle vane 9c of the turbocharger 9 is
So that the control to reduce the aperture greatly (decrease the opening) is performed
You may do it. In this case, the deviation Δλ₁₂(Or Δλ _Ten)But
Depending on whether the value is positive or negative, that is, the actual excess air ratio λ₁Eyes
Excess air ratio λ₀(Or limit target excess air ratio λ_Two)Than
The magnitude of the predetermined value E varies depending on whether
Further (for example, the predetermined value E₁, E_Two) Prefer to set
No.

A control device for an internal combustion engine as one embodiment of the present invention is configured as described above, and the supercharging pressure control and the EGR amount control by this device are performed as follows. First, the processing procedure of the main routine for the supercharging pressure control and the EGR control by the present device will be described. As shown in the flowchart of FIG. 8, first, in step S10, the engine speed Ne and the engine load (by the load sensor 35) are determined. Average effective pressure Pm calculated based on the detected load
e), the engine coolant temperature Tw detected by the engine coolant temperature sensor 36 is acquired in step S20, and the process proceeds to step S30, where the engine coolant temperature Tw detected by the engine coolant temperature sensor 36 is set to a predetermined value. It is determined whether or not the temperature is lower than Tw0.

As a result of this determination, if it is determined that the engine cooling water temperature Tw detected by the engine cooling water temperature sensor 36 is lower than a predetermined temperature Tw0, it is determined that the engine is in a cold state, and the process proceeds to step S40. The average effective pressure Pme calculated based on the engine rotation speed Ne detected by the engine rotation speed sensor 34 and the load detected by the load sensor 35 is further increased as shown in FIG. It is determined whether or not it belongs to the A zone. If the result of this determination is that it belongs to the A zone, it is an operation region in which the amount of generated HC in the low load operation region in the cold state is large, and thus the step S50 is performed. Then, the control in the cold state is performed. The details of the cold control will be described later.

On the other hand, if it is determined in step S40 that the fuel does not belong to the zone A, the HC in the low load operation region in the cold state is determined.
Is not in the operation region where the generation amount of
Then, normal control is performed. The details of the normal control will be described later. If it is determined in step S30 that the engine cooling water temperature Tw detected by the engine cooling water temperature sensor 36 is equal to or higher than a predetermined temperature Tw0, it is determined that the engine is in a hot state.
Proceeding to 60, normal control is performed. The details of the normal control will be described later.

Next, the processing procedure of the control in the cold state by the present apparatus will be described. As shown in the flowchart of FIG. 9, first, in step A10, the supercharging pressure control means 52 determines the opening degree of the nozzle vane 9c of the turbocharger 9. Is controlled to the maximum (full open) so that the supercharging pressure (in manifold pressure) is reduced. As a result, in the low load operation region in the cold state where the amount of generated HC is large, the supercharging pressure is reduced and the intake air amount is reduced, whereby the combustion temperature in the cylinder is increased and the turbocharger 9 is increased. Also increases the turbine outlet temperature, so that the HC generation level can be kept low. Further, since the combustion temperature increases, the exhaust gas temperature also increases accordingly, and the HC by the exhaust gas purifying catalyst 19
Purification efficiency is also at a high level, and HC emissions are reduced.

Next, at step A20, the actual excess air ratio λ
Step A:
30 and the actual air excess ratio
The remainder ratio λ1 is calculated. Specifically, the intake pressure sensor 32,
Detected by the atmospheric pressure sensor 33 and the intake air temperature sensor 31
Detection value P_mani,P_a,T_maniAnd load this
Intake temperature T _mani, A preset reference intake manifold temperature T
0 (for example, about 25 ° C.), engine speed Ne, engine
From the reference volumetric efficiency map according to the load
Volume efficiency ηv0, engine speed Ne, engine load
Volume efficiency index obtained from the volume efficiency index map according to
Using the number m, the volume efficiency ηv is calculated by the above equation (1).
Confuse.

Next, the read intake manifold pressure P _mani,
Using the atmospheric pressure P _{a, the} intake manifold temperature T _mani , and a preset gas constant R, the specific weight γ _mani (P
_mani, P _a, seek a T _mani). And the specific weight γ _{mani
(P mani, P a, T} mani), using volumetric efficiency .eta.v, the engine rotational speed Ne, the preset engine stroke volume Vh, calculates the intake amount G _cyl by the formula (3).

Next, the suction amount G thus calculated
_{Using cyl} , the EGR amount G _egr calculated by the equation (6), the fuel injection amount Gf set to obtain the desired output, and the theoretical air amount L0, the actual excess air is calculated by the above equation (5). The rate λ (actual excess air rate λ1) is calculated. Next, in step A40, the target excess air ratio setting means 54 uses the limit target excess air ratio map prepared for each engine rotation speed and engine load region based on the engine rotation speed Ne and the engine load Pme to obtain the target limit air ratio. Excess air ratio λ
Read ₂

Then, in step A50, a deviation Δλ ₁₂ (= λ ₁₎ between the actual excess air ratio λ ₁ and the limit target excess air ratio λ ₂ is obtained.
1-? ₂₎ it is determined whether less or not than a minute amount epsilon _1, the result of this determination, if the deviation [Delta] [lambda] ₁₂ is determined to be small amounts epsilon ₁ or more, the flow advances to step A60, further real excess air or rate lambda ₁ is greater or smaller than the limit target excess air ratio lambda _2, ie the deviation [Delta] [lambda] ₁₂ it is determined whether the smaller or not than 0, the result of this determination, it is determined that the deviation [Delta] [lambda] ₁₂ is smaller than 0 In this case, the process proceeds to step A70, the opening degree of the EGR valve 15b is controlled to reduce the EGR amount, and the process returns to step A20. Thereafter, the processes of step A20 to step A70 are repeated.

[0073] On the other hand, in step A60, if the deviation lambda ₁₂ is determined to be 0 or more, the flow advances to step A80, E
In order to increase the GR amount, the opening degree of the EGR valve 15b is controlled, and the process returns to step A20. Thereafter, the processes of step A20 to step A60 and step A80 are repeated. By the way, after such processing is repeated, in step A50, the deviation Δλ ₁₂ (= λ ₁ −λ ₂ ) between the actual excess air ratio λ ₁ and the limit target excess air ratio λ ₂ is smaller than the minute amount ε _1. If it is determined to be smaller, the control in the cold state is terminated, and the routine returns.

Next, the processing procedure of the normal control by the present apparatus will be described. As shown in the flowchart of FIG. 10, first, in step B10, the supercharging pressure control means 52 obtains the supercharging pressure based on the supercharging map at the time of warming. The opening degree of the nozzle vanes 9c of the turbocharger 9 is controlled so that the target supercharging pressure is obtained. That is, the average effective pressure P calculated based on the engine speed Ne detected by the engine speed sensor 34 and the load detected by the load sensor 35.
7 stored in the controller 50 based on the
The target supercharging pressure is set by using the supercharging pressure map at the time of warming as shown in FIG. 3, and the turbocharger 9 is set so that the actual supercharging pressure (actual supercharging pressure) at the present time matches the target supercharging pressure. The opening of the nozzle vane 9c is controlled.

In this case, in the normal operation range, that is, the medium-speed / high-load operation range, the supercharging pressure is set to be high to suppress the generation of sulfate. Further, in the idling operation region, the supercharging pressure is set to be high in order to maintain the turbine speed of the turbocharger 9 at a high speed in order to improve the starting acceleration. Next, in step B20, the intake air amount data is fetched to estimate the actual excess air ratio λ1, and the process proceeds to step A30, where the actual excess air ratio estimating means 55 calculates the actual excess air ratio λ1.

Specifically, the intake pressure sensor 32 and the atmospheric pressure
Each detected by the sensor 33 and the intake air temperature sensor 31.
Detection value P_mani,P_a,T_maniLoad this intake air temperature
Degree T _mani, A preset reference intake manifold temperature T0 (for example,
About 25 ° C), engine speed Ne and engine load
Volumetric efficiency calculated from the standard volumetric efficiency map
ηv0, engine speed Ne, and engine load
Use volumetric efficiency index m obtained from volumetric efficiency index map
Then, the volume efficiency ηv is obtained by the above equation (1).

Next, the read intake manifold pressure P _mani,
Using the atmospheric pressure P _{a, the} intake manifold temperature T _mani , and a preset gas constant R, the specific weight γ _mani (P
_mani, P _a, seek a T _mani). And the specific weight γ _{mani
(P mani, P a, T} mani), using volumetric efficiency .eta.v, the engine rotational speed Ne, the preset engine stroke volume Vh, calculates the intake amount G _cyl by the formula (3).

Next, the suction amount G thus calculated
_{By using cyl} , the EGR amount G _egr calculated by equation (9), the fuel injection amount Gf set to obtain the desired output, and the theoretical air amount L0, the above equation (5) [equation (8) ] To calculate the actual excess air ratio λ (actual excess air ratio λ1).
Next, at step B40, the target excess air ratio setting means 5
4 reads a target excess air ratio λ ₀ from a target excess air ratio map prepared for each engine rotation speed and engine load region based on the engine rotation speed Ne and the engine load Pme.

Then, in step B50, the deviation Δλ ₁₀ (= λ ₁ −λ) between the actual excess air ratio λ ₁ and the target excess air ratio λ ₀ is obtained.
₀ ) is smaller than the minute amount ε _{2. If} the result of this judgment is that the deviation Δλ ₁₀ is equal to or larger than the minute amount ε ₂ , the process proceeds to step B60, and further the actual excess air ratio λ _It is determined whether ₁ is larger or smaller than the target excess air ratio λ ₀ , that is, whether the deviation Δλ ₁₀ (= λ ₁ −λ ₀ ) is smaller than 0, and as a result of this determination, the deviation Δλ ₁₀ is smaller than 0. If it is determined that the EGR amount is also smaller, the process proceeds to step B70, the opening degree of the EGR valve 15b is controlled to reduce the EGR amount, and the process returns to step B20.
To Step B70 are repeated.

[0080] On the other hand, in step B60, if the deviation lambda ₁₀ is determined to be 0 or more, the flow advances to step B80, E
In order to increase the GR amount, the opening degree control of the EGR valve 15b is performed, and the process returns to step B20. Thereafter, the processes of step B20 to step B60 and step B80 are repeated. By the way, after such processing is repeated, in step B50, a deviation Δλ ₁₀ (= λ ₁ −λ ₀ ) between the actual excess air ratio λ ₁ and the target excess air ratio λ ₀ is reduced by a small amount ε _2.
If it is determined that the value is smaller than the normal control, the control at the normal time is terminated and the routine returns.

Therefore, according to the control apparatus for an internal combustion engine according to the present embodiment, the supercharging pressure is controlled by fully opening the opening of the nozzle vane 9c by the supercharging pressure control means 52 in the low load operation range in a cold state. Therefore, the combustion temperature (hence the turbine outlet temperature) increases, the amount of generated HC is suppressed, and the HC purification efficiency of the exhaust gas purifying catalyst is further increased. , it is possible to significantly reduce the HC emission amount is advantageous in that it is possible to further significantly reduce the NO _X emissions by introducing EGR.

In particular, the EGR device 15 is controlled so that EGR is introduced as much as possible within a range where HC does not increase rapidly.
To accurately controlled based on the opening of the GR valve 15b to λ excess air ratio, while reliably prevent the emissions of rapid combustion is suppressed HC increases rapidly by a large amount the introduction of EGR, the NO _X There is also an advantage that it can be greatly reduced.

In the above-described embodiment, the EGR amount control means 53 is configured to perform the EGR control based on the excess air ratio λ. However, the EGR amount control means 53 performs the control to increase the EGR amount when the engine is cold. It may be configured as follows. Further, in the above-described embodiment, the intake air amount G _a are determined by the equation or a map, the intake air amount G _a, for example Karman vortex flow meter, hot wire (hot wire) airflow sensor of flowmeter (AFS ) May be used.

[0084] In this case, the intake air amount G _a is a detection value of the air flow sensor and Q (m ³ / s), is calculated by the following equation specific weight of the air of the air flow sensor unit as γ _{a, f} (10) You. G _a = Q × γ _{a, f} (10) where the specific weight γ _{a, f} is expressed by P _mani, T in the above equation (4).
The pressure P _a of the air flow sensor portion _{mani, f,} temperature T _a, is determined by substituting _f.

In the above-described embodiment, the supercharging pressure (in manifold pressure) is controlled by using the turbocharger with a variable nozzle vane. However, it is sufficient if the supercharging pressure (in manifold pressure) can be adjusted. . For example, the supercharging pressure may be adjusted using a turbocharger having a wastegate valve or a supercharger with a transmission.

In the above embodiment, the present invention is described as applied to a diesel engine.
If supercharging pressure control is performed while detecting knock by a knock sensor, the present invention can be applied to a gasoline engine (in particular, a direct injection type).

[0087]

As described above in detail, according to the control apparatus for an internal combustion engine according to the first aspect of the present invention, the supercharging pressure is reduced by the control means in the low load operation range in the cold state to reduce the HC. the amount was suppressed, it is possible to reduce the HC emission amount further increases the HC purification rate of the exhaust gas purifying catalyst, the NO _X emissions by introducing part of exhaust gases to the intake pipe by the exhaust gas recirculation means There is an advantage that it can be reduced.

[Brief description of the drawings]

FIG. 1 is a functional block diagram showing a control device for an internal combustion engine according to one embodiment of the present invention.

FIG. 2 is a schematic diagram showing an overall configuration of a control device for an internal combustion engine according to one embodiment of the present invention.

FIG. 3 is a schematic view showing a turbocharger with a variable nozzle vane provided in the internal combustion engine according to one embodiment of the present invention, wherein (A) shows a case where the nozzle vane opening is fully opened;
(B) shows the case where the nozzle vane opening is fully closed.

FIG. 4 is a diagram showing HC purification rate characteristics of an oxidation catalyst provided in an internal combustion engine according to one embodiment of the present invention.

FIG. 5 is a view showing a cold boost pressure map used in a cold state in the control device for the internal combustion engine according to one embodiment of the present invention.

FIG. 6 is a diagram for explaining supercharging pressure control and EGR control in a control device for an internal combustion engine according to one embodiment of the present invention, wherein (A) shows a relationship between a nozzle vane opening degree and a turbine outlet temperature and is a diagram showing the relationship between the EGR amount and NO _X emissions, (B) is a diagram showing a relationship between a relationship and EGR amount and NO _X emissions and nozzle vanes opening and HC emissions.

FIG. 7 is a diagram showing a hot boost pressure map used in a hot condition in the control device for an internal combustion engine according to one embodiment of the present invention.

FIG. 8 is a flowchart showing a processing procedure of a main routine for supercharging pressure control and EGR control by the control device for the internal combustion engine according to one embodiment of the present invention.

FIG. 9 is a flowchart showing a processing procedure of cold control of the control device for the internal combustion engine according to one embodiment of the present invention.

FIG. 10 is a flowchart showing a processing procedure of normal control (hot control) of the control device for the internal combustion engine according to one embodiment of the present invention.

[Explanation of symbols]

Reference Signs List 9 turbocharger (supercharger) 9c nozzle vane 15 EGR device (exhaust gas recirculation device, exhaust gas recirculation means) 15b EGR valve 19 exhaust gas purification catalyst 31 intake temperature sensor (intake temperature detection device) 32 intake pressure sensor (intake pressure detection device) , Boost pressure sensor) 33 Atmospheric pressure sensor (atmospheric pressure detecting means) 34 Engine rotational speed sensor (engine rotational speed detecting means) 35 Load sensor (accelerator opening degree sensor) 36 Engine cooling water temperature sensor 41 EGR valve upstream pressure sensor 42 EGR valve Downstream pressure sensor 43 EGR valve upstream temperature sensor 44 EGR valve lift sensor 50 Controller (ECU) 51 Cold state determination means 52 Supercharging pressure control means 53 Exhaust gas recirculation amount control means (EGR amount control means) 54 Target excess air ratio setting means 55 Estimation of actual excess air ratio Stage

──────────────────────────────────────────────────続 き Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI Theme coat ゛ (Reference) F02B 37/12 302 F02B 37/12 302A F02D 21/08 311 F02D 21/08 311B 23/00 23/00 J F02M 25/07 550 F02M 25/07 550C 570 570P F-term (reference) 3G005 DA02 EA16 FA35 GA04 GC05 GE01 HA12 JA00 JA02 JA12 JA13 JA23 JA38 JB05 3G062 AA01 AA05 BA00 CA02 DA01 GA02 GA06 GA10 GA13 GA13 GA21 GA10 EB09 EB12 FA01 FA02 FA11 FA18 FA20 FA33 FA37 3G091 AA10 AA11 AA18 AA19 AB01 BA14 BA15 CB00 DC01 EA01 EA03 EA06 EA16 EA20 FA04 HB05 HB06 3G092 AA02 AA06 AA17 AA18 AB03 DB03 DC09 EA01 FA02

Claims (1)

[Claims] 1. A control device for an internal combustion engine comprising: an exhaust gas purifying catalyst in an exhaust passage; a supercharger for supercharging intake air; and exhaust gas recirculation means for recirculating a part of exhaust gas into the intake passage. A cold state determining means for determining whether or not the internal combustion engine is in a cold state; and Control means for reducing the supply pressure and increasing the amount of exhaust gas recirculated by the exhaust gas recirculation means.